The integration of digital processing technology with imaging devices has enabled more powerful and easier to use photographic products. For example, the ability to digitally control the shutter speed of an imaging device, aperture, and sensor sensitivity has provided for improved picture quality in a variety of imaging environments without the need for a photographer to manually determine and set these parameters for each environment.
Imaging devices having an automatic focusing capability (imaging devices and methods of which may be referred to herein simply as “autofocus”) has also made capturing high quality photographs easier by enabling almost any photographer, regardless of skill, to obtain a clear image in most imaging environments. Autofocus may have also reduced the workload of professional photographers. This may enable the photographers to focus more of their energies on the creative aspects of their trade, with a corresponding increase in the quality of photographs produced by these photographers.
Existing autofocus search operations may result in several problems. For example, the search time for the optimal lens position may be longer due to the imaging device having to search in both directions, near and far, thus resulting in delay before a properly focused image may be captured. Because of this the rate of failed autofocusing may increase and the user may have an undesired experience because of defocusing at the beginning of the autofocus search operation instead of receiving a progressively sharper focus. As a result, during an autofocus search operation the user may view an image that is slightly out of focus, the autofocus search operation may then cause the image to be increasingly defocused while the imaging device searches in the incorrect direction, and finally the imaging device may search in the opposite direction to locate the optimal focus position. There remains a need to remove this effect and minimize the time needed during an autofocus search operation.